SANTA CLARA, Calif. (AP) San Francisco 49ers linebacker Malcolm Smith suffered a torn pectoral muscle during Saturday's open practice at Levi's Stadium, putting in doubt the status of one of the team's most coveted offseason additions.

The team announced the injury Saturday night but had yet to make a roster move, and with not practicing again until Monday it provided a little bit of time for evaluation.

Smith, 28, left the field during full-team drills after working with the starters throughout training camp next to All-Pro NaVorro Bowman in the new-look defense.

"We think it was his chest area. Don't know for sure. But that's what it looked like," 49ers coach Kyle Shanahan said earlier in the day.

Smith, the MVP of Seattle's Super Bowl-winning team in the 2013 season, was brought in by San Francisco on a five-year contract in March. He rejoined new coordinator Robert Saleh, who was an assistant on the Seahawks' title team. Smith was expected to help transition to the new 4-3 scheme that's similar to what he ran with Seattle.

"That'd be a big one for us, just because we've been getting so many reps together, jelling together and really talking about what the offense is trying to do to us throughout these OTAs and in training camp," Bowman said of potentially losing Smith.

If Smith is sidelined, it may expedite first-round pick Reuben Foster's insertion into the starting lineup. Foster, 23, fell to the 31st selection in the NFL draft after he was widely expected to be a top-10 pick. The 49ers traded back into the first round to take Foster and said he was one of the top-three players on their draft board.

The Alabama alum won the Butkus Award last season and would be Smith's likely replacement. He ascended to working with the second string this week during team drills after being limited in the offseason program while recovering from shoulder surgery.

Veteran Ray-Ray Armstrong is also an option. He replaced Smith in the starting lineup Saturday as the weak-side inside linebacker during the full-team session.

"Reuben can definitely come downhill and smack you. They're both two smart guys," Bowman said. "I think at linebacker you have to smart, patient, know when you can shoot your gun and go make those plays."

The 49ers might also be without second-year guard Joshua Garnett, who sustained a knee injury that could require surgery.

"We don't know exactly, for sure, but there's some stuff in his knee we're probably going to have to clean up," Shanahan said. "I don't think it's anything long term, but it's going to take a little bit of time."

Garnett, a first-round pick in 2016, was competing with Zane Beadles for the starting left guard spot after starting 11 games at right guard as rookie.

---

For more NFL coverage: http://www.pro32.ap.org and http://www.twitter.com/AP-NFL